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| United States Patent |
5,353,660
|
|
Heck
|
October 11, 1994
|
Locking mechanism
Abstract
The invention pertains to a locking mechanism consisting of a guide lever
arm (1) and a sliding lever arm (5), in which one end of each of the lever
arm pivots about a bearing (10, 11) at a certain distance from the other
lever arm, in which the other end of the sliding lever arm (5).is
slidingly coupled with a slot (4) in the other end of the guide lever arm
(1) by a pin (7) connected with the sliding lever arm (5), and in which
the lever arms can be swiveled into two end positions. A force (2) exerted
on the guide lever arm (1) in one of the end positions for the purpose of
swiveling the guide lever arm (1) into the other end position is
compensated in a selflocking way in the slot (4) by a recess in the area
of the other end of the guide lever arm (1), and this locking effect can
be removed only by a force (6) exerted on the sliding lever arm (5) in the
direction of the other end position.
| Inventors:
|
Heck; Thomas (Mainz, DE)
|
| Assignee:
|
General Motors Corporation (Detroit, MI)
|
| Appl. No.:
|
022041 |
| Filed:
|
February 24, 1993 |
Foreign Application Priority Data
| Mar 03, 1992[DE] | 420662298 |
| Current U.S. Class: |
74/96; 16/82; 49/346; 292/268; 454/139 |
| Intern'l Class: |
G05G 005/06; E05C 017/16; E05F 003/22 |
| Field of Search: |
74/96
16/82
49/346
292/268
|
References Cited
U.S. Patent Documents
| 613171 | Oct., 1898 | McLaren | 49/346.
|
| 1148375 | Jul., 1915 | Gallup | 74/96.
|
| 2185486 | Jan., 1940 | Wahlberg | 454/139.
|
| 2235642 | Mar., 1941 | Lintern et al. | 454/139.
|
| 3639943 | Feb., 1972 | Cadiou | 16/82.
|
| 3980331 | Sep., 1976 | Kennedy et al. | 16/82.
|
| 4651583 | Mar., 1987 | Suzuki | 74/96.
|
| 4653689 | Mar., 1987 | Sakurai et al. | 237/12.
|
| 5244273 | Sep., 1993 | Kaspar et al. | 16/82.
|
| Foreign Patent Documents |
| 3904570 | Aug., 1989 | DE.
| |
| 2407114 | May., 1979 | FR.
| |
| 61-181717 | Aug., 1986 | JP.
| |
| 1-204815 | Aug., 1989 | JP | 74/96.
|
Primary Examiner: Herrmann; Allan D.
Attorney, Agent or Firm: Griffin; Patrick M.
Claims
I claim:
1. Locking mechanism consisting of a guide lever arm and sliding lever arm,
in which one end of each of the lever arms pivots about a bearing at a
certain distance from the other lever arm, in which the other end of the
sliding lever arm is slidingly coupled with a slot in the other end of the
guide lever arm by a pin connected with the sliding lever arm, and in
which the lever arms can be swiveled into two end positions, characterized
by the fact that a force (2) exerted on the guide lever arm (1) in one of
the end positions for the purpose of swiveling the guide lever arm (1)
into the other end position is compensated in a self-locking way in the
slot (4) by a recess (3) in the area of the other end of the guide lever
arm (1), said recess having an arc-shaped surface with a sectoral cutout
angle greater than 180 degrees and a diameter which is only slightly
greater than the width of the slot (4), so that the recess (3) merges with
the slot (4), and that this self locking effect can be removed only by a
force (6) exerted on the sliding lever arm (5) in the direction of the
other end position.
Description
The invention pertains to a locking mechanism consisting of a guide lever
arm and a sliding lever arm, in which one end of each of the lever arms
pivots about a bearing at a certain distance from the other lever arm, in
which the other end of the sliding arm is slidingly coupled with a slot in
the other end of the guide lever arm by a pin connected with the sliding
lever arm, and in which the lever arms can be swiveled into two end
positions.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 4,651,583 describes a locking mechanism. The locking effect
is brought about by the action of a spring, which is supported on the
stationary bearing of the guide lever arm and holds the pin of the sliding
lever arm pressed into the given end position. In accordance with the
state of the art, the locking mechanism is swiveled by compressing the
spring and causing the pin to slide in the groove until the two lever arms
swivel into the other end position, and the spring effect is activated and
the end position is thus secured.
A locking mechanism of this type has the disadvantage that, when the
swiveling occurs from one end position to the other, force must be
continuously applied against the action of the spring. Furthermore the
spring is an additional component that complicates a mechanism that is
relatively simple in itself.
SUMMARY OF THE INVENTION
The goal of the present invention was to modify a locking mechanism of the
type described in the introductory clause of claim 1 in such a way that a
locking effect would be achieved without additional components and that
less operating force would be needed to swivel from one end position to
the other end position.
This goal is achieved in accordance with the invention in such a way that a
force exerted on the guide lever arm in one of the end positions for the
purpose of swiveling the guide lever arm into the other end position is
compensated in a self-locking way in the slot by a recess in the area of
the other end of the guide lever arm, and that this locking effect can be
removed only by a force applied to the sliding lever arm in the direction
of the other end position.
The locking mechanism of the invention has the important advantage that no
additional components are required for locking, but rather it is only
necessary to cut out a longitudinal slot, and a large self-locking force
is achieved, which is greater than comparable spring forces in accordance
with the state of the art. In this connection, only the reaction force of
the sliding lever arm is utilized, which is supported on its bearing
against a forced exerted on the guide lever arm from the outside.
The design of the slot provides for the recess in the area of the other end
of the guide lever arm to have an arc-shaped surface with a sectoral
cutout angle greater than 180 degrees and a diameter which is only
slightly greater than the width of the slot itself. The guide lever arm
can be acted on by a force directed against the given end position by a
mechanical system coupled with the guide lever arm, but it is not brought
into the other end position by this force, but rather remains self-locked
in its present position. To remove the locking effect, a force is
transmitted to the sliding lever arm by a control element and a mechanical
device that engages the sliding lever arm. In a preferred embodiment of
the invention, the mechanical device is a Bowden cable attached to the pin
of the sliding lever arm, and the control element is a sliding control
element. In a preferred example of the invention, the mechanical system
coupled with the guide lever arm is a flap of a fan system of a motor
vehicle for selective adjustment of the operating mode to fresh-air
operation or circulating-air operation as the two corresponding end
positions of the locking mechanism. In another example of the invention,
the coupled mechanical system is the engine hood with the open and closed
states as the two corresponding end positions. In a third example of the
invention, the mechanical system coupled with the guide lever arm is the
sliding roof with a stand-up position and with the open and closed states
as the two corresponding end positions.
Additional advantageous designs of the invention are specified in the
subclaims.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Examples of the invention are shown in the drawings.
FIG. 1 shows the basic action of the locking mechanism.
FIG. 2 shows an enlarged section of FIGURE 1.
FIG. 3 shows an application of the locking mechanism to the position of the
flaps of an automotive fan system.
FIG. 4 shows the vectorial force relationships in the basic mode of
operation of the locking mechanism of the invention.
The locking mechanism shown in FIG. 1 consists of the guide lever arm (1)
and a sliding lever arm (5), in which one end of each of the lever arms
pivots about a bearing (10) or (11) at a certain distance from the other
lever arm in which the other end of the sliding lever arm (5) is slidingly
coupled with a slot (4) in the other end of the guide lever arm (1) by a
pin (7) connected with the sliding lever arm (5), and in which the lever
arms can be swiveled into two end positions. The guide lever arm (1) is
mechanically coupled with, for example, a flap (9), to which, under
certain conditions, a force is applied, which tries to swivel the guide
lever arm (1) into the other end position. This force (2) for swiveling
from this end position into the other end position is counteracted by
providing a recess (3) in the slot (4) in the area of the other end of the
guide lever arm (11), which slot compensates this force in a selflocking
way, and the locking can be removed only by a force (6) exerted on the
sliding lever arm (5) in the direction of the other end position. The
recess (3) is characterized by an arc-shaped surface with a sectoral
cutout angle greater than 180 degrees, and it has a diameter only slightly
greater than the width of the slot (4), so that the recess (3) merges with
the slot (4). The force (6) is applied to the sliding lever arm (5) by a
Bowden cable (8) at the pin (7). This allows the locking mechanism to move
from one end position to the other, such that in each of the end positions
forces (2) are applied, for example, to the flap (9). Since the recess (3)
runs symmetrically to the axis of the slot (4), it has its effect in each
of the two end positions. The diameter of the pin (7) corresponds
approximately to the width of the slot (4), and the pin can slide in the
slot analogously to an inclined plane. The basic action of the selflocking
will be explained with references to FIG. 4. The guide lever arm (1) is
drawn schematically. It pivots about the bearing (10), and the sliding
lever arm (5) is shown only with reference to the reaction force as a
vectorial symbol that acts from the bearing (11) as the source. 20
designates a force which, for example, can originate from the flat (9) of
FIG. 1. This force is counteracted by the reaction force (30), which is
applied from the bearing (11), and is resolved in a force parallelogram
into a tangential component and a component that acts on the bearing (11).
This component is compensated by the force (30), while the sliding lever
arm (5) is shifted to the right by the tangential component (40). In this
connection, the tangential component (40) rapidly becomes smaller until it
reaches a magnitude of 0. In this case, the action force (21) and the
reaction force (31) equally oppose and compensate each other. If the force
(21) is increased by pressure on the guide lever arm (1), the reaction
force (31) also increases. Since the tangential component (41) is 0, the
sliding lever arm (5) does not move. It remains in place. Only after the
pin (7) slides out of the area of the recess (3), which is possible only
if a force is exerted on the pin via the Bowden cable (8) or similar
mechanical device in the direction of the other end position, can the
sliding lever arm (5) slide along the slide surfaces of the slot (4), or a
force, which then acts on the guide lever arm (1), moves the pin (7) of
the sliding lever arm (5) in the direction of the other end position. This
is illustrated with the parallelogram of forces (22), (32) and (42), which
shows that with the amount after a constant force (22), a significantly
greater tangential component (42) is achieved.
FIG. 3 shows a practical application. The guide lever arm (1) is shown with
slot (4) and recess (3), in which pin (7) of the sliding arm (5) slides.
One of the end positions is indicated by broken lines. In the present end
position, which is indicated by solid lines, the guide lever arm is
coupled with a flap (9), at the end of which a rubber lip (14) is
attached, which is designed to compensate for any variations in clearance.
The rubber lip (14) fits tightly against a housing (19), which contains,
for example, an automotive fan (16) with an impeller (15). In the example,
shown here, the fan sucks air (17) through the fresh-air opening (22),
resulting in the development of a vacuum space (18) in front of the
impeller (15). This vacuum produces a force (2) on the flat (9) and tries
to move the flap (9) out of this end position, which would mean that
circulating air would also be sucked in by the fan. This is counteracted
by the self-locking action of the locking mechanism, for the coupling of
the flap (9) with the guide lever arm (1) results in the development of
force relationships in the recess, as was specified in the explanations to
FIG. 4. The flap is able to move into the position "circulating-air
operation" only when a force (6) is applied to the sliding lever arm (5)
via the Bowden cable (8), which is attached to the pin (7), to remove the
self-locking, effect of the locking mechanism. The same conditions apply
in the other end position, in which the fresh-air supply (12) is closed,
and circulating air (13) is drawn in by the fan.
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